Time period started getting observed in 1968 under then-President Lyndon Johnson

A bust of President Lyndon Johnson is seen in the U.S. Capitol prior to a Capitol Hill luncheon (Brendan Hoffman/Getty Images).

National Hispanic Heritage Month is held annually from mid-September to mid-October, but what does that mean, exactly?

In fact, there’s a website dedicated to answering this very question.

The month is dedicated to “celebrating the histories, cultures and contributions of American citizens whose ancestors came from Spain, Mexico, the Caribbean and Central and South America,” hispanicheritagemonth.gov explains.

The time period was first observed in 1968 under President Lyndon Johnson.

It started as Hispanic Heritage Week, until President Ronald Reagan expanded it to a month in 1988. This is when the 30-day window started covering Sept. 15 to Oct. 15.

It was enacted into law on August 17, 1988.

Why Sept. 15 as a kickoff day? You might ask.

The day is significant because it marks the anniversary of independence for Latin American countries Costa Rica, El Salvador, Guatemala, Honduras and Nicaragua.

In addition, Mexico and Chile celebrate their independence days on Sept. 16 and Sept. 18, respectively.

Also, Columbus Day or Día de la Raza, which is Oct. 12, falls within this 30 day period.